Battery module case and battery module including same

Abstract

The battery module case according to the embodiment of the present invention has a stepped structure to improve welding defects, thereby increasing the bonding strength between the components of the case and improving the yield of the battery module.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0065689 filed on May 27, 2022 and Korean Patent Application No. 10-2023-0062507 filed on May 15, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated by reference into this specification.

[0002] The present invention relates to a battery module case and a battery module including the same. [Background technology]

[0003] Generally, types of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, lithium-ion polymer batteries, etc. These secondary batteries are used not only in small products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, portable game devices, power tools, and E-bikes, but also in large products that require high output such as electric vehicles and hybrid vehicles, as well as in power storage devices and backup power storage devices that store surplus generated power and new renewable energy.

[0004] To manufacture such a secondary battery, first, an electrode active material slurry is applied to a positive electrode collector and a negative electrode collector to manufacture a positive electrode and a negative electrode, which are then laminated on both sides of a separator to form an electrode assembly of a predetermined shape, and the electrode assembly is then housed in a battery case, an electrolyte is injected, and the battery case is sealed.

[0005] In this way, a battery cell is manufactured by housing the electrode assembly in a battery case and injecting an electrolyte. A plurality of battery cells are housed in a frame-shaped case in a state where they are connected to each other to protect them from external shocks, heat, vibration, etc. In this way, a battery module is manufactured, and then a battery pack can be completed by providing the battery module with a control structure such as a BMS (Battery Management System).

[0006] In the process of housing battery cells in a battery module case and welding the battery module case, a problem of low battery module yield due to poor welding may occur. Therefore, there is a need for a battery module case having a structure that can facilitate welding of the battery module case and increase the bonding strength of the weld. Summary of the Invention [Problem to be solved by the invention]

[0007] One problem to be solved by the present invention is to provide a battery module case that improves welding defects. [Means for solving the problem]

[0008] A battery module case according to an embodiment of the present invention includes a main body including a bottom plate and a pair of side plates connected to both sides of the bottom plate, end plates connected to the main body and covering front and rear surfaces of the main body located at the front and rear of the main body in a longitudinal direction of the bottom plate, and a cover plate connected to the main body and covering one side of the main body parallel to the longitudinal direction of the bottom plate, and one side of the bottom plate connected to the end plate may be formed in a stepped shape.

[0009] The bottom plate may include a main body portion and step portions formed in a stepped shape at both ends of the main body portion.

[0010] The end plate may be coupled and connected to the stepped portion.

[0011] The end plate may include a coupling portion that is recessed to correspond to a shape of the stepped portion.

[0012] When viewed from the side plate, the joining portion includes a first surface connected to the underside of the end plate and perpendicular to the underside, and a second surface connected to the first surface and perpendicular to the first surface, and the step portion joins with the first surface and the second surface, thereby enabling the end plate and the main body to be joined to each other.

[0013] When viewed from the side plate, the step portion may be formed in a stepped shape from both sides of the main body portion toward the center of the main body portion, and the front and rear surfaces may be formed via the step portion and the side plate.

[0014] The thickness of the step portion may be greater than the thickness of the main body portion.

[0015] The thickness of the step portion may be 1.2 mm or more. Effect of the Invention

[0016] According to a preferred embodiment of the present invention, by improving welding defects, the bonding strength between the components of the case can be increased, and the yield of the battery module can be improved.

[0017] In addition, the present invention can include other effects that can be easily predicted by a person skilled in the art from the configuration according to the preferred embodiment of the present invention. [Brief description of the drawings]

[0018] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical ideas of the present invention. The present invention should not be interpreted as being limited solely to the matters depicted in such drawings.

[0019] [Figure 1] 1 is a perspective view of a battery module case according to an embodiment of the present invention; [Diagram 2] FIG. 2 is an exploded view of a battery module case according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a perspective view of a body according to an embodiment of the present invention. [Figure 4] 2 is a cross-sectional view of the battery module case taken along the line AA' in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in various different forms and is not limited to the following embodiments.

[0021] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the description or related known technologies that may obscure the gist of the present invention have been omitted, and when referring to components in each drawing in this specification, the same or similar reference symbols will be used for the same or similar components throughout the specification.

[0022] Furthermore, the terms and words used in this specification and the claims should not be interpreted in a limited manner to their ordinary or dictionary meanings, but should be interpreted in a manner that is consistent with the technical idea of ​​the present invention, based on the principle that the inventors can appropriately define the concepts of terms in order to best describe their invention.

[0023] FIG. 1 is a perspective view of a battery module case 10 according to an embodiment of the present invention.

[0024] Referring to FIG. 1, the battery module case 10 can accommodate a cell assembly, which will be described later, by forming an accommodation space therein. The battery module case 10 can protect the cell assembly from external environments such as external impact and heat by accommodating the cell assembly therein with one side open. The battery module case 10 can also be manufactured by accommodating the cell assembly therein with one side open, and assembling and welding the open part. For example, the battery module case 10 can be manufactured by covering and welding the front surface M1 and the rear surface M2 of a hexagonal frame with the front surface M1 and the rear surface M2 open. In the process of welding the battery module case 10, the battery module case 10 can be welded more firmly due to a stepped structure of a part of the battery module case 10. Specifically, the bonding force between each component of the battery module case 10 can be increased by adjusting the thickness of each part to be welded.

[0025] FIG. 2 is an exploded view of the battery module case 10 according to the embodiment of the present invention.

[0026] Referring to FIG. 2, the battery module case 10 may include a body 100, an end plate 101 and a cover plate 102.

[0027] The main body 100 may be a frame that serves as a reference when manufacturing the battery module case 10. In other words, the main body 100 may be a frame with one side open, which forms an accommodation space and is assembled with an end plate 101 and a cover plate 102 described below. Specifically, the main body 100 may have a hexagonal structure having a longitudinal direction and an open front surface M1 and a open rear surface M2 relative to the longitudinal direction. The main body 100 may also have a structure in which one surface M3 parallel to the longitudinal direction is open. According to this structure, the main body 100 may have a hexagonal shape with three open surfaces.

[0028] FIG. 3 is a perspective view of a body 100 according to an embodiment of the present invention.

[0029] 3, the main body 100 may include a bottom plate 1000 and a side plate 1001. For example, the bottom plate 1000 may form the lower surface of the main body 100. With the bottom plate 1000 forming the lower surface of the main body 100, the side plates 1001 may be connected to both sides of the bottom plate 1000. In other words, the side plates 1001 may be connected in pair to both sides of the bottom plate 1000 based on the longitudinal direction of the bottom plate 1000. In this case, the side plates 1001 may be connected perpendicularly to the bottom plate 1000. As a result, a front surface M1 and a rear surface M2 formed by one side of the bottom plate 1000 and one side of the pair of side plates 1001 may be formed.

[0030] The bottom plate 1000 may be partially formed in a stepped shape. For example, the bottom plate 1000 may include a main body portion 1000a and a stepped portion 1000b. The main body portion 1000a may be located in the center of the bottom plate 1000 and may have a plate shape with a constant thickness. The stepped portion 1000b is a portion connected to both ends of the main body portion 1000a and may include a stepped shape. Specifically, the stepped portion 1000b may be connected to both ends of the main body portion 1000a connected to the end plate 101, rather than to both ends of the main body portion 1000a connected to the side plate 1001. In other words, the stepped portion 1000b may be connected to both ends of the main body portion 1000a constituting the above-mentioned front surface M1 and rear surface M2. That is, the front surface M1 and rear surface M2 may be formed via the stepped portion 1000b and the side plate 1001.

[0031] More specifically, the step portions 1000b may be formed in a stepped shape from both sides of the main body portion 1000a toward the center of the main body portion 1000a when the side plate 1001 is viewed. Also, the thickness of the step portions 1000b may be greater than the thickness of the main body portion 1000a. That is, when the side plate 1001 is viewed, the bottom plate 1000 may have a structure in which the step portions 1000b are formed to protrude upward on both sides of the main body portion 1000a when the main body portion 1000a is located at the center.

[0032] The end plates 101 can be connected to the main body 100 so as to cover the front surface M1 and the rear surface M2 of the main body 100. In other words, the end plates 101 can be configured in a pair to be located at the front and rear of the main body 100 and connected to the main body 100.

[0033] FIG. 4 is a cross-sectional view of the battery module case taken along line AA' of FIG.

[0034] 4, the end plate 101 may be coupled and connected to the stepped portion 1000b. Specifically, the end plate 101 may include a coupling portion 1010 that is recessed to correspond to the shape of the stepped portion 1000b. For example, when viewed from the side plate 1001, the coupling portion 1010 may include a first surface 1010a, a second surface 1010b, and a third surface 1010c.

[0035] The first surface 1010a may be connected to the lower surface 101a of the end plate 101 and may be perpendicular to the lower surface 101a. The second surface 1010b may be connected to the first surface 1010a and may be perpendicular to the first surface 1010a. Finally, the third surface 1010c may be connected to the second surface 1010b and may be perpendicular to the second surface 1010b. In this case, the step portion 1000b may be inserted toward the first surface 1010a and may be coupled to the first surface 1010a and the second surface 1010b and welded together with the extension line of the lower surface 101a of the end plate 101 and the extension line of the lower surface of the step portion 1000b coinciding with each other, thereby allowing the end plate 101 and the main body 100 to be coupled to each other.

[0036] The following describes the contents and results of an experiment to measure the weldability between the main body 100 and the end plate 101. Specifically, the length of a weld defect that occurs in the process of welding the step portion 1000b and the end plate 101 is measured.

[0037] More specifically, a drain hole is formed in the center of the step portion 1000b, and the step portion 1000b has portions to be welded on both sides of the drain hole. In this case, the length of the welded portion on one side is 85 mm. In the experiment, when the welded portion on one side is welded, the thickness L of the step portion 1000b is 85 mm. 1 The length of the weld defect that occurs depending on the welding speed is measured.

[0038] Thickness L of step portion 1000b 1 The results of measuring the length of the weld defects that occurred depending on the welding conditions are shown in Table 1 below.

[0039] [Table 1]

[0040] Referring to Table 1, the thickness L of the step portion 1000b 1 It is recognized that the length of the weld defect is reliably reduced when the thickness L of the step portion 1000b is 1.1 mm or more. 1 The thickness L of the step portion 1000b may be 1.1 m or more. 1 The thickness L of the step portion 1000b can be set to 1.2 mm or more. 1 When the welding length is 1.2 mm or more, it is found that the length of the weld defect is significantly reduced.

[0041] In addition, when the thickness of the joint portion of the end plate 101 is taken into consideration, the thickness L of the step portion 1000b is 1 can be 1.5 mm or less. Based on the cross section shown in Fig. 4, the sum of the thicknesses of step portion 1000b and end plate 101 can be 3 mm. In other words, the thicker step portion 1000b is, the thinner the end plate 101 can be.

[0042] Thickness L of step portion 1000b 1 If the thickness L of the step portion 1000b is more than 1.5 mm, the thickness of the end plate 101 is reduced, and the welding bondability may be deteriorated due to the property of penetrating the end plate 101 from the step portion 1000b to melt and bond. 1 can be no larger than the thickness of the end plate 101.

[0043] As a result, the thickness L of the step portion 1000b of the bottom plate 1000 according to the embodiment of the present invention 1 When the gap is designed to be 1.2 mm to 1.5 mm, the weldability between the bottom plate 1000 and the end plate 101 can be greatly improved.

[0044] In this manner, by adjusting the thickness of the step portion 1000b relative to the main body portion 1000a, the main body 100 and the end plate 101 can be welded with a stronger bonding force, which prevents the battery module case 10 from being damaged due to the strong bonding force, and significantly increases the yield of the battery module.

[0045] The cover plate 102 may be connected to the body 100 to cover one surface M3 of the body 100 parallel to the longitudinal direction of the bottom plate 1000. For example, the one surface M3 may refer to the upper surface M3. In this case, the cover plate 102 may be connected to the body 100 to cover the open upper surface M3 of the body 100.

[0046] The following describes a battery module manufactured in the above-mentioned battery module case 10. When describing a battery module according to an embodiment of the present invention, duplicated content related to the above-mentioned battery module case 10 will be omitted below.

[0047] The battery module according to the embodiment of the present invention includes a cell assembly structure accommodated inside a battery module case 10, and is capable of storing electrical energy and outputting the stored electrical energy to the outside through a connection terminal.

[0048] For example, a cell assembly may be manufactured by forming a plurality of electrode cells, each of which has an electrode assembly therein and is activated by injecting an electrolyte therein, that is, the cell assembly may be a collection of a plurality of batteries.

[0049] The battery module case 10 accommodates such a cell assembly inside and is welded to block any alternating current between the cell assembly and the external space, thereby protecting the cell assembly from external factors such as impact and heat.

[0050] Specifically, the battery module case 10 may include a main body 100, an end plate 101, and a cover plate 102. The main body 100 may also include a bottom plate 1000 and a side plate 1001, and the bottom plate 1000 may include a main body portion 1000a and a step portion 1000b.

[0051] As described above, by adjusting the thickness of the step portion 1000b, the length of the weld defect between the main body 100 and the end plate 101 can be reduced, and the bonding strength between the main body 100 and the end plate 101 can be increased. As a result, the possibility of damage to the battery module is reduced, and the yield of the battery modules in the process of manufacturing the battery modules can be increased.

[0052] The above description is merely an illustrative example of the technical concept of the present invention, and various modifications and variations are possible by those having ordinary knowledge in the technical field to which the present invention pertains, without departing from the essential characteristics of the present invention.

[0053] Therefore, the embodiments disclosed in the present invention are intended to explain the technical idea of ​​the present invention and are not intended to limit the scope of the technical idea of ​​the present invention.

[0054] The scope of protection of the present invention should be interpreted according to the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention. [Explanation of symbols]

[0055] 10 Battery module case 100 Body 101 End plate 102 Cover plate 1000 Bottom Plate 1001 Side Plate 1000a Main body part 1000b Step 1010 Joining part 1010a 1st page 1010b 2nd side 1010c 3rd page 101a Underside of end plate M1 front M2 rear M3 one side L 1 Thickness of step L 2 Body thickness

Claims

1. a main body including a bottom plate and a pair of side plates connected to both sides of the bottom plate; end plates that cover the front and rear surfaces of the main body and are located in front and rear of the bottom plate in a longitudinal direction and are connected to the main body; a cover plate that covers one surface of the body parallel to a longitudinal direction of the bottom plate and is connected to the body; The battery module case has a side of the bottom plate connected to the end plate that is formed in a stepped shape.

2. The bottom plate is A main body part, The battery module case according to claim 1 , further comprising step portions formed in a stepped shape at both ends of the main body portion.

3. The battery module case according to claim 2 , wherein the end plate is coupled and connected to the stepped portion.

4. The battery module case according to claim 3 , wherein the end plates include a coupling portion that is recessed to correspond to a shape of the stepped portion.

5. When viewed from the side plate, the coupling portion includes a first surface that is connected to a lower surface of the end plate and perpendicular to the lower surface, and a second surface that is connected to the first surface and perpendicular to the first surface, The battery module case according to claim 4 , wherein the end plates and the main body are coupled to each other by the stepped portions being coupled to the first surface and the second surface.

6. When the side plate is viewed from the side, the step portion is formed in a step shape from both sides of the main body portion toward the center of the main body portion, The battery module case according to claim 2 , wherein the front and rear surfaces are formed via the stepped portion and the side plate.

7. The battery module case according to claim 6 , wherein the step portion has a thickness greater than a thickness of the main body portion.

8. The battery module case according to claim 7 , wherein the stepped portion has a thickness of 1.2 mm or more.

9. A battery module case according to any one of claims 1 to 8, and a cell assembly housed inside the battery module case.

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